Burial-induced

Light and Burial-Induced Changes in the Color and Tensile Properties... 

Burial-Induced Color Changes. Burial of dyed and dyed-mor-danted wool and silk fabrics had a profound effect on the color and depth of shade of the fabrics (Table III). Soil burial caused darking and extremely large changes in shade in most dyed fabrics, whereas the mordanted-dyed fabrics showed less deepening and change in shade than the unmordanted-dyed fabrics. 

Table 111. Burial-Induced Color Changes in Dyed and Dyed-Mordanted Wool and Silk Fabrics...

Intermediate subsystem of burial-induced groundwater flow Lateral flow of groundwater is away from the depocentre and focussed along unconformities and through relatively permeable, sandy, silty and limestone units... 

Figure 2.9 Cross-section showing hypothetical distribution of the three subsystems of burial-induced groundwater flow (geological cross-section of the Viking Graben, North Sea, adapted from Doligez et al., 1987. Reprinted by permission of Graham and Trotman Ltd.).

Figure 2.10 Characteristic pressure-depth relations in the three subsystems of burial-induced groundwater flow.

The shallow and intermediate subsystems of burial-induced groundwater flow may develop in shaly basins with moderate subsidence rates (0.1 mm - 1 mm/year). In rapidly subsiding shaly basins (burial rates > 1 mm/year), all three subsystems may occur. 

Figure 2.13 Calculated directions and velocities of burial-induced groundwater flow in a subsiding inhomogeneous basin, after 50 and 100 million years of subsidence (after Bethke, 1985, Journal of Geophysical Research, Vol. 9, no. B8, Fig. 5, p. 6822. Copyright by the American Geophysical Union).

In addition to the grovmdwater pressure distribution, the burial-induced flow of groundwater is associated with several physical and chemical characteristics of the sedimentary basin. These include the distribution of temperature, salinity and chemical composition of the groundwater, and the distribution of diagenetic minerals in the basin. 

The flow of water through a semi-permeable membrane (clay, shale) from water with a small concentration of dissolved solids to water with a greater concentration is called osmosis (e.g. Bredehoeft et al., 1982 Neuzil, 1986). The osmotically-induced flow of water occurs because of a difference in vapour pressure across the membrane (Hinch, 1980). The aqueous activity will be relatively small in water with a relatively large concentration of dissolved solids, because more water molecules are bonded on the dissolved ions (Hinch, 1980). In a sandstone-shale sequence with water of equal chemical concentration, the aqueous activity of the shale water will be less than that of the sandstone-water, because water molecules are adsorped on the large mineral surfaces of the shale (Hinch, 1980). As a consequence, the water salinity differences that may exist in sandstone-shale sequences in the intermediate and deep subsystems of burial-induced groundwater flow may actually be in osmotic equilibrium. 

---